1. Field of the Invention
This invention relates to a variable discharge surge feeder and bolter for receiving, handling and discharging material received from a continuous mining machine and ultimately discharged to a shuttle car and more particularly to a system for continuously operating a material receiving conveyor while periodically interrupting the discharge of material therefrom corresponding with the shuttle car position.
2. Description of the Prior Art
Conventional modern continuous mining machines move progressively and continuously into a mine vein. As an integral part of such machines, a rearwardly moving conveyor accepts disintegrated material adjacent the face of the mine and transports it rearwardly through the mining machine for discharge at the rear end thereof. During the operation of the mining machine, the flow of this material emerging from the mining machine conveyor is continuous.
Material emerging from the mining machine is ultimately placed in a shuttle car, which when filled travels away from the mine area to be unloaded. A problem is created as a result of the mining machine at one end of this system operating continuously, while the shuttle car is available to accept materials only intermittently. If the mining machine is to be operated substantially continuously and thereby mine a maximum amount of material within a given time, it is necessary for compensation to be made in the material transporting system in order to avoid intermittent shutdowns during the travel and unloading period of the shuttle car. Without arranging for some compensating means, the continuously operating conveyor would simply discharge the mined material onto the mine floor during the time period within which the shuttle car was not in material receiving position.
One means of compensating for this time delay created by shuttle car handling is disclosed in U.S. Pat. No. 2,290,950 wherein an intermediate hopper car is positioned between the mining machine and the shuttle car and is adapted to receive mined material from the mining machine conveyor and ultimately transfer it to the shuttle car. The hopper car disclosed includes a transport conveyor and provides storage capacity for the disintegrated material being received during a period when discharge is not permitted. The car also has adjustable means by which the amount of material entering the storage area and the amount moving on to the shuttle car may be controlled. One disadvantage of the storage facility is that it requires the manual adjustment of an adjustable deck in order to control the volume of flow into the storage area. It, therefore, does not provide automatic means for adjusting flow into the storage compartment.
In U.S. Pat. No. 2,670,836 a material handling car is provided with two conveyors. In operation, the receiving conveyor transfers material to the discharge conveyor which, in turn, transfers the material to the shuttle car. Provision is made for shuttle car removal by stopping the receiving conveyor and speeding up the discharge conveyor to empty it. At that point the shuttle car may be removed and both conveyors are operated at a very slow speed to continue the transfer of material from the receiving to the discharge conveyor. This is accomplished at such a low speed, however, that no material leaves the discharge end of the discharge conveyor until the shuttle car has returned. Thus, this system provides for shuttle car travel and unloading by synchronized speed adjustments between the two conveyors. A similar system is illustrated and disclosed in U.S. Pat. No. 2,753,971 wherein a double receiving conveyor is provided in tandem. The second of these two conveyors discharges material into a small storage container which has a conveyor and ultimately transfers the material to a final discharge conveyor. In order to terminate discharge at the far end of the tandem conveyors, the conveyor located within the storage area is stopped. When the shuttle car has returned to its loading position, the intermediate conveyor is started once again.
A system employing a flight conveyor wherein periodic termination of discharge is sought to be effected is disclosed in U.S. Pat. No. 2,637,457. In this system a number of the flights are removed thereby providing for automatic termination of the discharge from the conveyor at a certain point within each revolution of the continuous conveyor. The removal of flights and the timed movement of the shuttle car with respect to the conveyor must, however, be very carefully coordinated. The system has the disadvantage of being relatively inflexible.
There is need for an apparatus for the handling of dislodged particulate material which coordinates the continuous delivery of disintegrated material from the mining machine with intermittent transmission to a shuttle car. While it has been suggested to provide intermediate storage capacity, the prior art systems require either a multiplicity of conveyors and either stoppage of one conveyor or coordinated speed changes of the respective conveyors with respect to each other and the shuttle car.